怎样使用OpenCV进行人脸识别

Posted 2023-04-30

参考技术A opencv有人脸识别的库，你可以直接调用opencv安装包里也有历程，一般是先灰度化图片，然后二值处理，再利用函数就可以识别出有人脸的矩形区域

怎么用opencv自带的分类器进行人脸识别

帮忙给出具体的步骤！

（安装opcv环境）
代码：
#include "cv.h"
#include "highgui.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <math.h>
#include <float.h>
#include <limits.h>
#include <time.h>
#include <ctype.h>

#ifdef _EiC
#define WIN32
#endif

static CvMemStorage* storage = 0;
static CvHaarClassifierCascade* cascade = 0;

void detect_and_draw( IplImage* image );

const char* cascade_name =
"haarcascade_frontalface_alt.xml";
/* "haarcascade_profileface.xml";*/

int main( int argc, char** argv )

CvCapture* capture = 0;
IplImage *frame, *frame_copy = 0;
int optlen = strlen("--cascade=");
const char* input_name;

if( argc > 1 && strncmp( argv[1], "--cascade=", optlen ) == 0 )

cascade_name = argv[1] + optlen;
input_name = argc > 2 ? argv[2] : 0;

else

cascade_name = "../../data/haarcascades/haarcascade_frontalface_alt2.xml";
//opencv装好后haarcascade_frontalface_alt2.xml的路径,
//也可以把这个文件拷到你的工程文件夹下然后不用写路径名cascade_name= "haarcascade_frontalface_alt2.xml";
//或者cascade_name ="C:\\\\Program Files\\\\OpenCV\\\\data\\\\haarcascades\\\\haarcascade_frontalface_alt2.xml"
input_name = argc > 1 ? argv[1] : 0;


cascade = (CvHaarClassifierCascade*)cvLoad( cascade_name, 0, 0, 0 );

if( !cascade )

fprintf( stderr, "ERROR: Could not load classifier cascade\\n" );
fprintf( stderr,
"Usage: facedetect --cascade=\\"<cascade_path>\\" [filename|camera_index]\\n" );
return -1;

storage = cvCreateMemStorage(0);

if( !input_name || (isdigit(input_name[0]) && input_name[1] == \'\\0\') )
capture = cvCaptureFromCAM( !input_name ? 0 : input_name[0] - \'0\' );
else
capture = cvCaptureFromAVI( input_name );

cvNamedWindow( "result", 1 );

if( capture )

for(;;)

if( !cvGrabFrame( capture ))
break;
frame = cvRetrieveFrame( capture );
if( !frame )
break;
if( !frame_copy )
frame_copy = cvCreateImage( cvSize(frame->width,frame->height),
IPL_DEPTH_8U, frame->nChannels );
if( frame->origin == IPL_ORIGIN_TL )
cvCopy( frame, frame_copy, 0 );
else
cvFlip( frame, frame_copy, 0 );

detect_and_draw( frame_copy );

if( cvWaitKey( 10 ) >= 0 )
break;


cvReleaseImage( &frame_copy );
cvReleaseCapture( &capture );

else

const char* filename = input_name ? input_name : (char*)"lena.jpg";
IplImage* image = cvLoadImage( filename, 1 );

if( image )

detect_and_draw( image );
cvWaitKey(0);
cvReleaseImage( &image );

else

/* assume it is a text file containing the
list of the image filenames to be processed - one per line */
FILE* f = fopen( filename, "rt" );
if( f )

char buf[1000+1];
while( fgets( buf, 1000, f ) )

int len = (int)strlen(buf);
while( len > 0 && isspace(buf[len-1]) )
len--;
buf[len] = \'\\0\';
image = cvLoadImage( buf, 1 );
if( image )

detect_and_draw( image );
cvWaitKey(0);
cvReleaseImage( &image );


fclose(f);





cvDestroyWindow("result");

return 0;


void detect_and_draw( IplImage* img )

static CvScalar colors[] =

0,0,255,
0,128,255,
0,255,255,
0,255,0,
255,128,0,
255,255,0,
255,0,0,
255,0,255
;

double scale = 1.3;
IplImage* gray = cvCreateImage( cvSize(img->width,img->height), 8, 1 );
IplImage* small_img = cvCreateImage( cvSize( cvRound (img->width/scale),
cvRound (img->height/scale)),
8, 1 );
int i;

cvCvtColor( img, gray, CV_BGR2GRAY );
cvResize( gray, small_img, CV_INTER_LINEAR );
cvEqualizeHist( small_img, small_img );
cvClearMemStorage( storage );

if( cascade )

double t = (double)cvGetTickCount();
CvSeq* faces = cvHaarDetectObjects( small_img, cascade, storage,
1.1, 2, 0/*CV_HAAR_DO_CANNY_PRUNING*/,
cvSize(30, 30) );
t = (double)cvGetTickCount() - t;
printf( "detection time = %gms\\n", t/((double)cvGetTickFrequency()*1000.) );
for( i = 0; i < (faces ? faces->total : 0); i++ )

CvRect* r = (CvRect*)cvGetSeqElem( faces, i );
CvPoint center;
int radius;
center.x = cvRound((r->x + r->width*0.5)*scale);
center.y = cvRound((r->y + r->height*0.5)*scale);
radius = cvRound((r->width + r->height)*0.25*scale);
cvCircle( img, center, radius, colors[i%8], 3, 8, 0 );



cvShowImage( "result", img );
cvReleaseImage( &gray );
cvReleaseImage( &small_img );


然后按照程序的位置（看代码）放入训练好的xml：
haarcascade_frontalface_alt.xml和haarcascade_frontalface_alt2.xml这些网上可以搜到，楼主找不到可以问我要（QQ：1207643343） 参考技术A 一轮小月亮，细小而洁白得犹如唯一的茉莉花
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